POS0970 SAME OR DIFFERENT? ANALYSIS OF SIMILARITIES AND DIFFERENCES OF CROHN’S DISEASE AND ULCERATIVE COLITIS IN SPONDYLOARTHRITIS: AN ANCILLARY ANALYSIS FROM THE WORLDWIDE ASAS-perSpA STUDY.
Authors: V. Rios Rodriguez, T. Izci Duran, M. Torgutalp, C. López-Medina, M. Dougados, M. Kishimoto, K. Ono, S. Lüders, M. Protopopov, H. Haibel, J. Rademacher, D. Poddubnyy, F. Proft
Journal: Annals of the Rheumatic Diseases (2022)

Background Crohn’s disease (CD) and ulcerative colitis (UC) are grouped as inflammatory bowel disease (IBD), and both are frequently found as extra-musculoskeletal manifestations in spondyloarthritis (SpA). Several studies have described the connection between SpA and IBD in both directions. Still until today, no studies have investigated possible differences in the musculoskeletal manifestations between the two main entities of inflammatory bowel disease: CD and UC. Objectives To evaluate the clinical characteristics associated with the presence of CD or UC in patients with spondyloarthritis from the international cross-sectional ASAS-perSpA study. Methods We analyzed 3152 patients from the ASAS per-SpA cohort who had a diagnosis of axial SpA or peripheral SpA according to the treating rheumatologist. Patients with IBD - confirmed by endoscopy - were identified and stratified by CD or UC. Patients in which their IBD disease was not specified, were excluded. Demographics, clinical characteristics, treatments and patient-reported outcomes were compared between both subgroups. Results Among the 146 patients diagnosed with IBD from the 3152 patients included in the analysis, 87 (59.6%) presented with CD (75 patients with axial SpA and 12 with peripheral SpA) and 39 (26.7%) with UC (34 patients with axial SpA and 5 with peripheral SpA) - Figure 1. A total of 20 (13.7%) patients with IBD were excluded, due to an inconclusive diagnosis of IBD. Patients with CD and UC had similar age (44.9 vs 44.0 years old) and sex distribution, although a slightly higher frequency of males was observed in CD than UC (63.2% vs 51.3%). The diagnostic delay for SpA was 7.0 years for CD and 8.1 years for UC. We did not find differences between both groups related to any musculoskeletal manifestations such as chronic back pain, uveitis, arthritis, enthesitis or dactylitis (Table 1). The only parameter showing a significant difference between CD and UC was the Bath Ankylosing Spondylitis Functional Index (BASFI) with a mean score of 3.3 vs 2.2 respectively (p=0.02) (Table 1). CD patients showed a higher tendency to be HLA-B27 positive (51.9% in CD vs. 39.4% in UC), but this did not reach statistical significance. No differences were observed regarding treatment patterns between both groups. Table 1. Demographics and clinical characteristics related to spondyloarthritis of patients with concomitant Crohn’s disease or ulcerative colitis (n=146). Crohn’s Disease N=87 Ulcerative Colitis N=39 P Age, mean (SD) 44.9 (13.5) 44.0 (13.0) 0.68 Sex, n/N (%) male 55/87 (63.2) 20/39 (51.3) 0.21 Smoker ever, n/N (%) 36/87 (41.4) 19/39 (48.7) 0.44 Diagnostic delay of SpA (years), mean (SD) 7.0 (6.9) 8.8 (8.1) 0.38 Psoriasis ever, n/N (%) 9/87 (10.3) 6/39 (15.4) 0.47 Uveitis ever, n/N (%) 17/87 (19.5) 11/39 (28.2) 0.28 Synovitis ever, n/N (%) 42/87 (48.3) 18/39 (46.2) 0.83 Enthesitis ever, n/N (%) 26/87 (29.9) 14/39 (35.9) 0.50 Dactylitis ever, n/N (%) 3/87 (3.4) 1/39 (2.6) 0.79 Axial involvement ever (according to the rheumatologist), n/N (%) 79/87 (90.8) 37/39 (94.9) 0.44 Sacroiliitis on X-ray, n/N (%) 64/87 (73.6) 26/39 (66.7) 0.19 HLA-B27 positive, n/N (%) 28/54 (51.9) 13/33 (39.4) 0.26 CRP mg/L, mean (SD) 11.1 (33.8) 15.3 (30.1) 0.13 ASDAS-CRP, mean (SD) 2.4 (1.0) 2.4 (1.1) 0.84 BASFI, mean (SD) 0-10 3.3 (2.6) 2.2 (2.1) 0.02 csDMARDs ever, n/N (%) 71/87 (81.6) 35/39 (89.7) 0.25 bDMARDs ever, n/N (%) 72/87 (82.8) 33/39 (84.6) 0.80 ASDAS, Ankylosing Spondylitis Disease Activity Score; BASFI, Bath Ankylosing Spondylitis Functional Index; bDMARD, biological disease-modifying antirheumatic drugs; CRP, c-reactive protein; csDMARD, conventional synthetic disease-modifying antirheumatic drugs; SD, standard deviation; SpA, spondyloarthritis. Conclusion In our ancillary analysis of the ASAS-perSpA study in patients with SpA and concomitant CD or UC, no differences in the clinical presentation or demographic characteristics between the two subgroups were observed, except for the BASFI. Disclosure of Interests None declared